Conformational flexibility and ligand binding properties of ovine β-lactoglobulin

Loch, J.I.; Bonarek, Piotr; Lewiński, K.

doi:10.18388/abp.2019_2883

Cited by 7 publications

(7 citation statements)

References 29 publications

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“…In turn, the random conformed proteins have very low ellipticity above 210 nm and one band near 195 nm [ 20 ]. The main conformation of β-LG is β-sheet at pH close to physiological [ 4 , 21 , 22 , 23 , 24 , 25 , 26 ]. Oligomeric state is dependent in particular on pH; at pH 2.0 it is a stable monomer, while at neutral pH it shows a dimeric state.…”

Section: Introductionmentioning

confidence: 99%

Isolation and Self-Association Studies of Beta-Lactoglobulin

Gołębiowski

Pomastowski

Rodzik

et al. 2020

IJMS

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The aim of this study was to investigate isolated β-lactoglobulin (β-LG) from the whey protein isolate (WPI) solution using the column chromatography with SP Sephadex. The physicochemical characterization (self-association, the pH stability in various salt solutions, the identification of oligomeric forms) of the protein obtained have been carried out. The electrophoretically pure β-LG fraction was obtained at pH 4.8. The fraction was characterized by the matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/TOF MS) technique. The use of the HCCA matrix indicated the presence of oligomeric β-LG forms, while the SA and DHB matrices enabled the differentiation of A and B isoforms in the sample. The impact of sodium chloride, potassium chloride, ammonium sulfate, and sodium citrate in dispersion medium on β-LG electrophoretic stability in solution was also studied. Type of the dispersion medium led to the changes in the isoelectric point of protein. Sodium citrate stabilizes protein in comparison to ammonium sulfate. Additionally, the potential of capillary electrophoresis (CE) with UV detection using bare fused capillary to monitor β-LG oligomerization was discussed. Obtained CE data were further compared by the asymmetric flow field flow fractionation coupled with the multi-angle light scattering detector (AF4-MALS). It was shown that the β-LG is a monomer at pH 3.0, dimer at pH 7.0. At pH 5.0 (near the isoelectric point), oligomers with structures from dimeric to octameric are formed. However, the appearance of the oligomers equilibrium is dependent on the concentration of protein. The higher quantity of protein leads to the formation of the octamer. The far UV circular dichroism (CD) spectra carried out at pH 3.0, 5.0, and 7.0 confirmed that β-sheet conformation is dominant at pH 3.0, 5.0, while at pH 7.0, this conformation is approximately in the same quantity as α-helix and random structures.

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Section: Introductionmentioning

confidence: 99%

Isolation and Self-Association Studies of Beta-Lactoglobulin

Gołębiowski

Pomastowski

Rodzik

et al. 2020

IJMS

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“…The curve shape was similar but more gently compared to that of pure DPPC monolayer, indicating that DPPC- β LG mixed monolayer is in an expanded state and has a more flexible and fluid structure compared to that of the DPPC-Al monolayer ( Figure 2 c). The specific flexibility of β LG [ 53 , 54 , 55 ] may contribute to the formation of an expanded mixed monolayer. Moreover, the mole ratio of DPPC: β LG = 129:1 corresponds to the A 0 ratio (nm 2 ) of DPPC: β LG = 76:14.8, making it suitable as a model biomembrane of a lipid–protein mixture as same as the DPPC-Al mixture.…”

Section: Resultsmentioning

confidence: 99%

The Interaction between Anesthetic Isoflurane and Model-Biomembrane Monolayer Using Simultaneous Quartz Crystal Microbalance (QCM) and Quartz Crystal Impedance (QCI) Methods

Yamamoto,

Ito,

Akatsuka

et al. 2024

Membranes

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The interaction between anesthetic Isoflurane (Iso) and model-biomembrane on the water surface has been investigated using quartz crystal microbalance (QCM) and quartz crystal impedance (QCI) methods. The model-biomembranes used were dipalmitoyl phosphatidyl choline (DPPC), DPPC-palmitic acid (PA) mixture (DPPC:PA = 8:2), DPPC-Alamethicin (Al) mixture (DPPC:Al = 39:1), and DPPC-β-Lactoglobulin (βLG) mixture (DPPC:βLG = 139:1) monolayers, respectively. The quartz crystal oscillator (QCO) was attached horizontally to each monolayer, and QCM and QCI measurements were performed simultaneously. It was found that Iso hydrate physisorbed on each monolayer/water interface from QCM and changed those interfacial viscosities from QCI. With an increase in Iso concentration, pure DPPC, DPPC-PA mixed, and DPPC-Al mixed monolayers showed a two-step process of Iso hydrate on both physisorption and viscosity, whereas it was a one-step for the DPPC-βLG mixed monolayer. The viscosity change in the DPPC-βLG mixed monolayer with the physisorption of Iso hydrate was much larger than that of other monolayers, in spite of the one-step process. From these results, the action mechanism of anesthetics and their relevance to the expression of anesthesia were discussed, based on the “release of interfacial hydrated water” hypothesis on the membrane/water interface.

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“…Interestingly, the transition is shifted to significantly higher pH in porcine βLg (Ugolini et al, 2001) while the EF loop is also mobile in the protein structures available for sheep (Kontopidis et al, 2014;Loch et al, 2014), goat (Crowther et al, 2014;Loch et al, 2015), reindeer (Oksanen et al, 2006) and pig (Hoedemaeker et al, 2002). As Glu 89 is very well conserved among the βLg homologues, it may be that there is functional significance in this observed gating (Qin et al, 1998;Ragona et al, 2003;Konuma et al, 2007;Loch et al, 2019), mimicked by simulation (Bello and García-Hernández, 2014;Bello, 2020;Fenner et al, 2020;Labra-Núñez et al, 2021), once again being consistent with a transport function (e.g., Sawyer, 2013;Edwards and Jameson, 2020).…”

Section: β-Lactoglobulinmentioning

confidence: 98%

β-Lactoglobulin and Glycodelin: Two Sides of the Same Coin?

Sawyer

2021

Front. Physiol.

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The two lipocalins, β-lactoglobulin (βLg) and glycodelin (Gd), are possibly the most closely related members of the large and widely distributed lipocalin family, yet their functions appear to be substantially different. Indeed, the function of β-lactoglobulin, a major component of ruminant milk, is still unclear although neonatal nutrition is clearly important. On the other hand, glycodelin has several specific functions in reproduction conferred through distinct, tissue specific glycosylation of the polypeptide backbone. It is also associated with some cancer outcomes. The glycodelin gene, PAEP, reflecting one of its names, progestagen-associated endometrial protein, is expressed in many though not all primates, but the name has now also been adopted for the β-lactoglobulin gene (HGNC, www.genenames.org). After a general overview of the two proteins in the context of the lipocalin family, this review considers the properties of each in the light of their physiological functional significance, supplementing earlier reviews to include studies from the past decade. While the biological function of glycodelin is reasonably well defined, that of β-lactoglobulin remains elusive.

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Conformational flexibility and ligand binding properties of ovine β-lactoglobulin

Cited by 7 publications

References 29 publications

Isolation and Self-Association Studies of Beta-Lactoglobulin

Isolation and Self-Association Studies of Beta-Lactoglobulin

The Interaction between Anesthetic Isoflurane and Model-Biomembrane Monolayer Using Simultaneous Quartz Crystal Microbalance (QCM) and Quartz Crystal Impedance (QCI) Methods

β-Lactoglobulin and Glycodelin: Two Sides of the Same Coin?

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